U.S. patent application number 16/966253 was filed with the patent office on 2021-02-11 for transmission system for control data.
The applicant listed for this patent is ZF Friedrichshafen AG. Invention is credited to Ingo Lippenberger, Michel Wetterau, Andreas Wildbrett.
Application Number | 20210044448 16/966253 |
Document ID | / |
Family ID | 1000005219105 |
Filed Date | 2021-02-11 |
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United States Patent
Application |
20210044448 |
Kind Code |
A1 |
Wetterau; Michel ; et
al. |
February 11, 2021 |
Transmission System for Control Data
Abstract
A control bus (165) permits the transmission of a message (205)
of a predetermined message length. A method (300) for transmitting
pieces of information on the control bus (165) includes
transmitting a message (205). The message includes a first field
(210) and a second field (215). The first field (210) contains a
variable reference to a type of information, and the second field
(215) contains a piece of information of the type of information
referred to in the first field (210).
Inventors: |
Wetterau; Michel;
(Meersburg, DE) ; Lippenberger; Ingo; (Horgenzell,
DE) ; Wildbrett; Andreas; (Bermatingen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ZF Friedrichshafen AG |
Friedrichshafen |
|
DE |
|
|
Family ID: |
1000005219105 |
Appl. No.: |
16/966253 |
Filed: |
January 10, 2019 |
PCT Filed: |
January 10, 2019 |
PCT NO: |
PCT/EP2019/050490 |
371 Date: |
July 30, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 69/329 20130101;
H04L 67/12 20130101; H04L 69/22 20130101; H04L 12/403 20130101 |
International
Class: |
H04L 12/403 20060101
H04L012/403; H04L 29/08 20060101 H04L029/08; H04L 29/06 20060101
H04L029/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2018 |
DE |
10 2018 201 433.7 |
Claims
1-9. (canceled)
10. A method for transmitting pieces of information on a control
bus, the control bus permitting transmission of a message of a
predetermined message length, the method comprising: transmitting a
message comprising a first field and a second field, wherein the
first field contains a variable reference to a type of information,
and wherein the second field contains a piece of information of the
type of information referred to in the first field.
11. The method of claim 10, wherein transmitting the message
comprises transmitting a plurality of messages one after the other,
and the reference of the first field changes in consecutive
messages.
12. The method of claim 11, wherein the reference of the first
field cyclically changes.
13. The method of claim 11, wherein the message comprises a fourth
field, the fourth field refers to one of a plurality of different
message types, and a predetermined cycle length is associated with
each message type.
14. The method of claim 13, wherein types of information of the
fields of the message are defined with respect to each message
type.
15. The method of claim 10, wherein the message further comprises a
third field, and the third field includes information of a fixedly
predetermined type of information.
16. The method of claim 15, wherein the message comprises a fourth
field, the fourth field refers to one of a plurality of different
message types, and a predetermined cycle length is associated with
each message type.
17. The method of claim 16, wherein types of information of the
fields of the message are defined with respect to each message
type.
18. The method of claim 10, wherein the control bus comprises a
master and at least one slave, and the master configured for
requesting, via a first message to the slave, a transmission of a
second message of a second message type from the slave.
19. The method of claim 18, wherein the variable reference of the
first message comprises a reference to a predetermined message type
of the cycle.
20. The method of claim 18, wherein the message comprises a fourth
field, the fourth field refers to one of a plurality of different
message types, and a predetermined cycle length is associated with
each message type.
21. The method of claim 20, wherein types of information of the
fields of the message are defined with respect to each message
type.
22. A device for transmitting pieces of information on a control
bus, the control bus permitting transmission of a message of a
predetermined message length, the device comprising: an interface
for connection to the control bus; and a control device configured
for transmitting a message, the message comprising a first field
and a second field, wherein the first field contains a variable
reference to a type of information, and wherein the second field
contains a piece of information of the type of information referred
to in the first field.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is related and has right of priority
to German Patent Application No. 10 2018 201 433.7 filed on Jan.
31, 2018 and to PCT Application Publication No. 2019/149488 filed
on Jan. 10, 2019, both of which are incorporated by reference in
their entirety for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a transmission
system for control data. In particular, the invention relates
generally to the flexible transmission of information between
different control devices with the aid of a control bus.
BACKGROUND
[0003] On board a motor vehicle, multiple control units are
communicatively networked with the aid of a control bus. The
control bus can permit the transmission on the initiative of any
type of control unit, or a master can be provided, which, as the
only one, can arbitrate the bus and prompt a slave to transmit a
message of a predetermined message type. Usually, messages to be
exchanged on the communication bus are limited in terms of length
and are subdivided into predetermined fields. One field usually
includes an address of a sender or recipient. One further field can
contain an identification of the message type. Both fields are
limited in terms of length, so that the number of bus users and/or
the number of different message types can also be limited.
[0004] In practical applications, a control task can be difficult
to implement within these limitations. For example, more different
types of messages may be necessary than can be defined with the aid
of the protocol of the control bus. In this case, the utilization
of a more complex control bus is frequently necessary, which
supports a greater bandwidth, a greater number of message types, or
greater volumes of user data. This also means, however, in general,
changed physical driver modules, possibly also other voltage
levels, another transmission medium, or another data-transmission
approach. An existing control unit can usually not be retrofitted
with a reasonable amount of effort. In addition, a certification of
the driver modules can be necessary in the case of a
safety-critical application, such as the open-loop control of an
aspect of a motor vehicle, and so a considerable effort may
possibly need to be made to exchange the control bus.
SUMMARY OF THE INVENTION
[0005] Example aspects of the present invention therefore provides
an improved technique, in order to be able to also perform a
control task that is complex or versatile with respect to data
transmission with the aid of a simple control bus.
[0006] A control bus permits the transmission of a message of a
predetermined message length. A method for transmitting pieces of
information on the control bus includes transmitting a message,
which includes a first field and a second field. The first field
contains a variable reference to a type of information, and the
second field contains a piece of information of the type of
information referred to by the first field.
[0007] As a result, different types of information can be
transmitted within one message, so that an increased number of
different pieces of information can be effectively addressed. Such
a limitation of the control bus can be overcome in this way.
[0008] Multiple messages can be transmitted one after the other,
wherein the reference of the first field is changed in consecutive
messages. This variant can be advantageous, in particular, for the
case in which the pieces of information of the second field are to
be transmitted at a low frequency.
[0009] The reference of the first field can be changed in a
cyclical manner. The pieces of information transmitted within the
second field can then have a predetermined repetition rate, which
can be lower than the repetition rate of the messages by the cycle
length.
[0010] The message can include a third field, which contains pieces
of information of a fixedly predetermined type of information.
Pieces of information that are to be transmitted frequently can be
transmitted in the third field. For example, control parameters of
a control device can be transmitted in the third field in every
message, while peripheral conditions that change only slowly, such
as a temperature of a controlled object, can be transmitted in the
second field. In particular when the first field is varied in a
cyclical manner, two different, fixed data rates can be implemented
in this way.
[0011] The control bus can include a master and at least one slave.
The master can request, with the aid of a first message to the
slave, a transmission of a second message of a second message type
from the slave. A bus controlled, by an open-loop system, by the
master can be more robust, and an arbitration phase can be omitted
or run in a simpler manner. The transmission of a message can be
better planned, in particular with respect to time. In one
particularly preferred embodiment, the first field can be
cyclically changed by the slave in consecutive messages. The method
can permit a simpler processing, in particular by the master.
[0012] The first message can contain a reference to a predetermined
message type of the cycle. In other words, the master can set an
index of the cycle in the event of any type of request for a second
message. Basically, this possibility can be utilized in order to
directly request a certain piece of information within the cycle.
The slave-side incrementation of the first field can be stopped, in
that the index is set by the master upon each request.
[0013] The message can also include a fourth field, which refers to
one of several different message types, wherein a predetermined
cycle length is associated with each message type. In this way, the
control bus can be operated in different transmission modes. One
transmission mode can correspond to one operating condition of a
terminal (master or slave). For example, a first message type can
be transmitted in the case of a system start, wherein this message
type can include a predetermined number of different messages. Each
of these messages can be transmitted one time. Therefore, the
system start can be concluded and messages of a second message type
can be transmitted in a normal operating mode. Once again,
cyclically different messages of the second message type can be
transmitted one after the other.
[0014] Types of information of the fields of a message can be
defined with reference to a message type. In other words, the
length of a field of a message can be constant in one message type,
but can be different between different message types.
[0015] A device for transmitting pieces of information on a control
bus, which permits the transmission of a message of a predetermined
message length, includes an interface for the connection to the
control bus and a control device. The control device is configured
for transmitting a message, which includes a first field and a
second field. The first field contains a variable reference to a
type of information, and the second field contains a piece of
information of the type of information referred to by the first
field.
[0016] The device is preferably configured for partially or
completely carrying out or controlling a method described herein.
The method can be present as a computer program product and can run
on a processing unit of the device. Advantages and features of the
method can be transferred to the device, and vice versa.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Example aspects of the invention will now be described more
precisely with reference to the attached figures, in which:
[0018] FIG. 1 shows an exemplary transmission system;
[0019] FIG. 2 shows a schematic of exemplary messages for
transmission on a control bus; and
[0020] FIG. 3 shows a flow chart of a method for transmitting
messages on a control bus.
DETAILED DESCRIPTION
[0021] Reference will now be made to embodiments of the invention,
one or more examples of which are shown in the drawings. Each
embodiment is provided by way of explanation of the invention, and
not as a limitation of the invention. For example, features
illustrated or described as part of one embodiment can be combined
with another embodiment to yield still another embodiment. It is
intended that the present invention include these and other
modifications and variations to the embodiments described
herein.
[0022] FIG. 1 shows a transmission system 100. A prime mover 105,
represented here as an internal combustion engine by way of
example, acts via a transmission 110 upon a drive shaft 115. The
transmission system 100 is preferably configured for driving a
motor vehicle, in particular a passenger car, and can include a
driving wheel, upon which the drive shaft 115 can act.
[0023] The transmission 110 can be controlled by an open-loop
system, in that, in particular, an engaged gear step is changed. If
the transmission 110 includes a converter clutch 120, parameters on
the converter clutch 120, such as a blade position or an activation
of a torque converter lockup clutch, are controllable by an
open-loop system. Preferably, a first control device 125 is
provided for the open-loop control of the transmission 110. Certain
operations within the transmission 110 can be hydraulically
controlled, for example, the disengagement or engagement of a
clutch or a brake. For this purpose, a predetermined fluid pressure
of a hydraulic fluid is necessary, which can be made available by a
pump 130. Oil, in particular, can be utilized as fluid. The oil can
be withdrawn, for example, from a forced oil lubrication of the
prime mover 105. Oil flowing out of the control device can then be
returned into an oil sump or at another point of the prime mover
105.
[0024] The pump 130 can be mechanically driven with the aid of the
prime mover 105, wherein a fluid pressure can be dependent on the
rotational speed of the prime mover 105. The pump 130 can be driven
with the aid of an electric motor 135. The electric motor 135 can
operate as a power-split auxiliary drive of the pump 130 in
addition to the prime mover 105, or the pump 130 can permit only
one single drive, so that the electric motor 135 can act upon the
pump 130 as an alternative to the prime mover 105.
[0025] The electric motor 135 can be controlled by an open-loop
system with the aid of a control device 140, which, in the
represented example embodiment, includes a bridge circuit 145 and a
determination unit 150 for determining voltages or currents to be
set. The bridge circuit 145 can be differently designed depending
on the type of the electric motor 135. In one preferred type of
construction, the electric motor 135 is designed as a brushless DC
motor (BLDC) including, more preferably, three phases. The bridge
circuit 145 can make three mutually independent voltages available
to the phases. For this purpose, each phase is connected between
the potentials of an intermediate circuit voltage with the aid of
two current valves. The current valves are opened and closed in
alternation, so that a predetermined voltage sets in at the
inductive load of the phase.
[0026] The determination unit 150 operates preferably with the aid
of field-oriented control (FOC) or field-oriented regulation (FOR),
in which, preferably, the rotational speed and/or the torque of the
electric motor 135 can be specified. The determination unit 150 can
be connected to a further control device 160 with the aid of an
interface 155. The control device 160 can be configured for the
open-loop control of any aspect or even multiple aspects of the
transmission system 100. For the communication between the control
device 140 of the electric motor and the control device 160 of the
transmission system 100, preferably a control bus 165 is provided,
to which the control device 125 of the transmission 110 can also be
connected. Optionally, one more control device or multiple further
control devices can be connected to the control bus 165, for
example, a control device 170 for the open-loop control of the
prime mover 105. Optionally, the control device 160 is also
connected to one further control bus, for example, a CAN bus,
wherein the control device 160 can transmit data between the two
busses (in the function of a "bridge").
[0027] The control bus 165 is preferably designed as a field bus
including a master and one slave or multiple slaves. In one example
embodiment, the control bus is designed as a LIN bus (LIN: Local
Interconnect Network), wherein the control device 160 is preferably
configured as a master. Other control busses are also possible,
however, for example, a CAN bus (CAN: Controller Area Network).
Preferably, this is a serial bus, which can make do with one wire,
in the case of the LIN bus, and with two wires, in the case of the
CAN bus, as the physical transmission medium.
[0028] The amount of information to be exchanged between the
control device 160 and the control device 140 of the electric motor
135 can be great. In particular, there can be a need to transport a
wide variety of different data in different operating conditions of
the transmission system 100 over the control bus 165. For this
purpose, the master can be configured for addressing a slave via
the control bus 165 and requesting that the slave return a
predetermined message. The slave usually responds immediately with
the requested message, which can include multiple predetermined
fields. Usually, only a limited number of messages can be defined,
due to a limitation of the length of a corresponding field. The
greater is the number of different pieces of information to be
transmitted, the greater is the number of messages that must be
defined, however. If disjoint messages are utilized, transmissions
of pieces of information needed less frequently can also imperil
the frequency of the transmission of more critical pieces of
information.
[0029] In the following description, it is assumed, by way of
example, that there is one master 160 and one slave 155, although
other constellations, in particular including multiple slaves or
including multiple masters, are also possible.
[0030] FIG. 2 shows, in an upper area, a message 205, which can be
transmitted on a control bus 165, and, in a lower area, three
different exemplary sequences of messages 205 on the control bus
165. The message 205 includes a first field 210 and a second field
215, in order to enable a multiplexing of pieces of information.
The second field 215 can contain different pieces of information.
Reference is made to the type of information thereof, in each case,
with the aid of a predetermined reference in the first field 210.
The reference in the first field 210 can be indicated, in
particular, as an index, for example, in the form of a numeral,
preferably in binary form. For example, different types of
information can be established for the first field 210, for which
12 different indices can be represented, as binary-coded decimals,
in the first field 210 of the length 4 bits (or longer). In a
simple example, the first field 210 can have, for example, the
index 1 if the second field 215 contains a measured temperature, or
the index 2 if the second field 215 contains an error code.
[0031] An optional third field 220 can include further bits of
information, the information type of which is constant at least
within one message type 230 through 240. The third field 220 can
also be internally subdivided, so that various pieces of
information, of invariable types of information in each case, can
be transmitted. In the third field 220, for example, a control
parameter, such as an internally determined specified rotational
speed or an actual rotational speed of the electric motor 135, can
be transmitted.
[0032] An optional fourth field 225 can indicate the message type
of the message 205. The length of the fourth field 225 is
preferably constant over all message types and is always located at
the same point with respect to the beginning of the message 205. If
the messages 205 of different message types have different lengths,
it is more preferable that the fourth field 225 be situated ahead
of a variable field of the message 205. In particular, the fourth
field 225 can be situated at the beginning of the message 205.
[0033] Different lengths of fields of the message 205 can be
associated with different message types. The messages 205 of
different message types preferably have the same length, although
the messages 205 of different message types can also have different
lengths. In particular, a predetermined supply of information types
of the second field 215 can be associated with one message type.
Preferably, an index is associated with each type of information,
so that a predetermined sequence of types of information results
from indices arranged in a strictly monotonous order (increasing or
decreasing). The sequence can be, in particular, cyclically
executed.
[0034] It is preferred that a predetermined part of a message 205
(preferably the last byte within a message 205) carries a checksum
(CRC) over the remaining transmitted pieces of information. This
applies, preferably, for all messages 205 that are transmitted in
any direction between the master 160 and the slave 155. The
checksum can be considered to be a separate static field or part of
the fourth field 225.
[0035] A transmission of messages 205 on the control bus 165
preferably takes place in such a way that a predetermined message
205 is sent by the master 160 to a predetermined slave 155. The
message 205 contains a request to provide a predetermined message
205, and the slave 155 responds with a message 205 containing the
sought information. Each message 205 of the slave 155 to the master
160 therefore needs an explicit preceding message 205 by the master
160.
[0036] In the present case, it is assumed that the control bus 165
is a LIN bus, in which the master 160 provides, for a response of a
slave 155, the start ("header") of a message frame on the control
bus 265 and, thereafter, the slave 155 transmits the requested
data. The request of the master 160 preferably has the same length
as a response message 205 of the slave 155, eight bytes in the
present case, preferably in addition to the header; this
corresponds to the maximum of the LIN specification. In the
represented example embodiment, the message 205 includes a CRC8
checksum in the last byte.
[0037] A request message 205 from the master 160 to the slave 155
can have a separate message type and can make do without the first
two fields 210 and 215. Pieces of information of the static third
field 220 can include, for example, a specified rotational speed of
the electric motor 135, an oil temperature of the prime mover 105,
or an estimated torque of the electric motor 135. Further bits can
include the index of a type of information of a message 205 to be
returned. A predetermined number of bits can be provided for
additional functions. Moreover, bits can be reserved at different
points of the message 205 for a subsequent use. Individual bits can
also be utilized for special functions, for example, one bit for
resetting a fault condition or one bit for displaying whether the
electric motor 135 is to run in the clockwise direction or in the
counterclockwise direction. In addition, an access counter (AC) can
be provided, which contains values cyclically incremented over the
individual messages 205. In this way, on the basis of the access
counter, a first message 205 from the master 160 to the slave 155
can be associated with a second message 205 from the slave 155 to
the master 160. In this way, a message 205 that became lost during
the transmission or was transmitted multiple times can be
noticed.
[0038] In the lower area of FIG. 2, three different message types
230, 235 and 240 are represented, by way of example, including
appropriate sequences of information types in the respective second
fields 215. Exemplary indices of the individual types of
information of the represented message types 230 through 240 are
represented in FIG. 2. The representation from FIG. 2 is based on a
standard message type 230, an identification message type 235, and
a development message type 240.
[0039] In the standard message type 230, the following exemplary
types of information can be provided:
TABLE-US-00001 Index Type of information 0 phase current phase U 1
intermediate circuit voltage at the point in time of the phase
current U 2 temperature of the control device 140 3 additional
functions 4 phase current phase V 5 intermediate circuit voltage at
the point in time of the phase current V 6 error indicators (1) 7
error indicators (2)
[0040] The standard message type 230 is usually transmitted at
fixed time intervals, provided the control device, the electric
motor 135, or the transmission system 100 is operating. Pieces of
information of the displayed types of information can be cyclically
transmitted from the slave 155 to the master 160.
[0041] At a selected transmission rate, a message 205 can be
transmitted within approximately 10 ms, so that, in the
aforementioned example, there can be approximately 40 ms between
the transmission of the phase current of the phase U and the
transmission of the phase current of the phase V due to the
particular necessary request messages 205 by the master 160. In
order to avoid a decorrelation of the intermediate circuit voltage
from the phase currents, pairs of phase currents and intermediate
circuit voltages corresponding thereto with respect to time are
transmitted in this case.
[0042] In the identification message type 235, the following types
of information, for example, can be provided.
TABLE-US-00002 Index Type of information 0 identification (1) 1
identification (2) 2 identification (3) 3 identification (4) 4
identification (5) 5 software version (1) 6 software version (2) 7
hardware version 8 checksum (CVN) over data memory of the software
(1) 9 checksum (CVN) over data memory of the software (2) 10
response identifier for OBD (1) 11 response identifier for OBD
(2)
[0043] The identification message type 235 can be utilized, for
example, when the control device 140 is initialized, for example,
during the start of a motor vehicle with the aid of the
transmission system 100. Identifiers of various components of the
transmission system 100 or of a surrounding motor vehicle can be
exchanged, in order to subsequently be able to ensure an operation
as specified. Typically, the identification message type 235 is
transmitted on the control bus 165 only one time per start of the
prime mover 105.
[0044] In the development message type 240, the following types of
information, for example, can be provided.
TABLE-US-00003 Index Type of information 0 phase current phase V 1
temperature of the control device 140 2 phase current phase U 3
intermediate circuit voltage at the point in time of the phase
current U 4 phase current phase V 5 rotor position 6 phase current
phase U 7 ignition angle 8 phase current phase V 9 temperature of
the control device 140 10 phase current phase U 11 intermediate
circuit voltage at the point in time of the phase current V 12
phase current phase V 13 generator voltage of the electric motor
135 or zero crossing, if necessary, for analyzing the rotor
position sensor 14 phase current phase U 15 PWM duty cycle
[0045] The development message type 240 can transmit certain pieces
of information more frequently or less frequently than the standard
message type 230; additional values can also be transmitted. The
development message type 240 can be advantageously utilized within
the scope of a development of components of the transmission system
100, in particular the pump 130, the electric motor 135, the
control device 140, or the control device 160, or even for a more
precise diagnosis, for example, in a workshop, for example, for
troubleshooting.
[0046] Additional message types can be provided, for example, for
transmitting fault conditions or for shutting off the electric
motor 135 or the control device 140. In one example embodiment, a
shut-off of all slaves 155 takes place if no message of the master
160 takes place on the control bus 165 past a predetermined time,
for example, approximately four (4) seconds.
[0047] The third field 220 of messages 205 of the message types 230
through 240 can always be occupied in the same manner and, for
example, include a specified rotational speed of the electric motor
135, the above-described access counter, or an index of the type of
information transmitted in the second field 215. Moreover, a
certain direction of rotation of the electric motor 135, an error
indicator, an indicator of a completed initialization of the
control device 140, and indicator of a communication error, a
transient fault, a permanent fault, or an indicator of a warning
about endangered data security. Remaining bits can be reserved for
a subsequent use.
[0048] FIG. 3 shows a flow chart of an exemplary method 300 for
transmitting messages 205 on a control bus 165. The method 300 is
preferably carried out in interaction between the master 160 and
the slave 155. In the representation from FIG. 3, the master is
arranged on the left, conceptually, and the slave 155 is arranged
on the right, conceptually, and the represented steps each relate
to a transmission of a message 205 from one party to the other
party, as indicated by the arrows.
[0049] In a first step 305, the master 160 transmits a first
message 205 to the slave 155, which contains a request to transmit
a second message 205 back. A predetermined message type 230 through
240, to which the response is to correspond, can also be indicated.
Optionally, the first message 205 can contain an index, to which
the value of the first field 210 of the requested second message
205 is to be set. If such a specification is not made, the slave
155, in its response, can assume a fixed index or determine an
appropriate index on its own.
[0050] In one step 310, the slave 155 responds to the master 160
with the requested second message 205. The fourth field 225 of the
message type is preferably set to the value of the fourth field 225
of the received first message 205, in order to display the utilized
message type. The first field 210 contains an index, which
indicates the type of information associated with the pieces of
information in the second field 215.
[0051] In one step 315, the master 160 transmits a third message
205 to the slave 155 with the request to transmit a fourth message
205. In this case, once again, a predetermined index can be
indicated for the first field 210 of the response, or the slave 155
can determine the index itself, in particular in that the slave 155
increments a corresponding counter. If its value exceeds the number
of defined types of information of the message type 230 through
240, the slave 155 can reset the index appropriately, so that, via
the transmitted messages 205, a cyclic transmission of pieces of
information of all agreed-upon types of information can take place.
Exemplary sequences of response messages 205 in the case of
sequential indexing are described in greater detail above with
reference to FIG. 2. An appropriate message 205 is transmitted from
the slave 155 to the master 160 in 320.
[0052] Such a sequence can be repeated at any frequency, in order
to continuously transmit pieces of information between the master
160 and the slave 155 in both directions. The pieces of information
of the fourth field 225 can be transmitted at a predetermined high
frequency. The frequency of the information transmitted from the
master 160 to the slave 155 is the same in this case. In the case
of a sequential order of the indices of the first field 210, the
defined fields are transmitted from the slave 155 to the master 160
at a correspondingly lower frequency. The master 160 can change the
sequence of the transmitted types of information at any time,
however, and, in this way, request pieces of information of certain
types of information more frequently or earlier.
[0053] Modifications and variations can be made to the embodiments
illustrated or described herein without departing from the scope
and spirit of the invention as set forth in the appended claims. In
the claims, reference characters corresponding to elements recited
in the detailed description and the drawings may be recited. Such
reference characters are enclosed within parentheses and are
provided as an aid for reference to example embodiments described
in the detailed description and the drawings. Such reference
characters are provided for convenience only and have no effect on
the scope of the claims. In particular, such reference characters
are not intended to limit the claims to the particular example
embodiments described in the detailed description and the
drawings.
REFERENCE NUMBERS
[0054] 100 transmission system [0055] 105 prime mover [0056] 110
transmission [0057] 115 drive shaft [0058] 120 converter clutch
[0059] 125 control device transmission [0060] 130 pump [0061] 135
electric motor [0062] 140 control device electric motor [0063] 145
bridge circuit [0064] 150 determination unit [0065] 155 interface
(slave) [0066] 160 control device transmission system (master)
[0067] 165 control bus [0068] 170 control device [0069] 205 message
[0070] 210 first field [0071] 215 second field [0072] 220 third
field [0073] 225 fourth field [0074] 230 first message type
(standard) [0075] 235 second message type (identification) [0076]
240 third message type (development) [0077] 300 method [0078] 305
request message (index n) [0079] 310 return message (index n)
[0080] 315 request message (index n+1) [0081] 320 return message
(index n+1)
* * * * *